Reminds me a little bit of Minecraft updates.

With Minecraft you have the Herobrine story - a player claimed in a video that another player named Herobrine was showing up in his offline game and causing chaos. He was trying to create a creepypasta rumour that Minecraft was haunted by the creator’s dead brother, and probably only failed because he was careless and let himself be caught on audio saying that’s what he was doing.

Ever since, the developers occasionally release update notes that include the line ‘removed Herobrine’.